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Farhan
Asked: 2012-08-10 08:35:22 +0800 CST

Linux different size for df and du for root partition

  • 772

On my CentOS server, both of the commands are showing different usage for disk / , df shows this output:

Filesystem            Size  Used Avail Use% Mounted on
/dev/xvda2             16G   14G  952M  94% /
/dev/xvda6            996M  258M  687M  28% /tmp
/dev/xvda3             16G  6.5G  8.3G  45% /var
/dev/xvda1            251M   25M  213M  11% /boot
tmpfs                 4.0G     0  4.0G   0% /dev/shm

and du -sh shows

6.9M    /bin/
15M /boot/
123M    /etc
212K    /home/
233M    /lib
27M /lib64/
16K /lost+found/
8.0K    /media/
8.0K    /mnt/
399M    /opt/
959M    /root/
35M /sbin/
8.0K    /srv/
0   /sys/
2.5G    /usr/
4.2G    total

Also tried with NCDU tool, which reports only 5.6GB usage.

How to find hidden disk space?

linux

3 Answers

  1. Best Answer

    See if you have any deleted files still in use

    lsof | grep deleted
    • 12

  2. There's a lengthy explanation to be found in any number of blogposts online with a quick search, but the basic gist is this:

    If I create a 1 GB sparse file, du will show 1 GB, but df will show zero usage. If I have a 1 GB file open in some program and delete it, df will still show 1 GB of usage until all references to the inode are closed, but du will never find the file to display it.

    • 1

  3. df is file system usage which includes files, and other structures that support the files such as journal etc. du only shows the file size sum which will mostly be less. the difference will depend how long the filesystem has been in use, the filesystem itself, etc.

    • 0